"n" is talk, "m" is talk but only your team can read it. There's also "," which sends a message to the person who last killed you, and "." which I believe sends a message to the person who you last messaged, or who last messaged you, or something to that extent.

You can go into "options" "input setting" "change key mapping" to define your own keys, or just to look at what the default keys are.

OS Moment <"O""S" mo·ment>
1) Where one can see something bad about to happen, cant do a bloody thing about it, but still has time to say "Oh 5h!t!!!" 2) An action that makes all the surrounding people drop their jaw and say "Oh 5h!t...."